Montgomery County Executive Charles W. Gilchrist and 33 other Democratic Party activists from the suburban county endorsed Maryland Attorney General Stephen H. Sachs yesterday in his bid to become the state's next governor.

Gilchrist, a longtime friend and ideological twin of Sachs, had been expected for months to endorse him over Mayor William Donald Schaefer of Baltimore, who plans to announce his own candidacy for governor formally later this month.

"Steve set a new tone of independence for top officeholders in the state and emphasized -- at a time when too many people were turning their back on it -- consumer affairs and the environment," said Gilchrist, who was flanked by Sachs at a news conference in Rockville.

In an apparent allusion to Schaefer, the premier advocate of Baltimore's interests, Gilchrist said Sachs had "taken care to be equitable to all parts of this state."

Gilchrist, who is leaving politics to study for the Episcopal priesthood, said he had "great respect" for Schaefer who, like Sachs, is a Democrat. But several persons familiar with Gilchrist's thinking said the county executive was privately troubled by some aspects of Schaefer's more conservative political philosophy -- and by the mayor's assertion last week that he supports weakening new programs designed to revive the Chesapeake Bay.

Schaefer suggested that recently enacted "critical areas" legislation, which would restrict development around the bay shoreline, be relaxed as early as next year. The mayor also said the state's ban on the catching of rockfish could be lifted "a couple of years from now" because the endangered fish population is apparently returning to a healthy size."Nothing has hurt Schaefer more in Montgomery County than the bay gaffes," said Stanton J. Gildenhorn, the coordinator of Sachs' campaign in Montgomery. "It really ticks off Democrats in this county."

However, Norman Locksley, Gildenhorn's counterpart in the Schaefer campaign, said the mayor's recent remarks "will in no way hurt him."

Joining Gilchrist and Sachs yesterday were more than a dozen other Democratic candidates, many of them newcomers to elective politics. Incumbent state Sen. S. Frank Shore and Dels. Gene W. Counihan and Jennie M. Forehand also endorsed Sachs.

Sachs, who was shown to be trailing Schaefer badly in recent statewide polls, said he was grateful for the "good old-fashioned Democratic commitment." He added: "History will record that my great come-from-behind victory, my upset victory, started right here in Montgomery."